This change isn’t permanent, meaning that when you leave recovery mode your system partition will revert back to read-only. It’s only temporarily writable so that you can get rid of those unwanted apps.

Connect your Desire via USB cable

Open the Command Prompt/Terminal on your computer (Start Menu > Run > Cmd)

Type: adb shell ls system/data
You should now see a list of all the apps (.apk files) in your system folder

For whichever apps you want to backup type:
adb pull system/app/<full_name_of_app.apk> <full_name_of_app.apk>
where <full_name_of_app.apk> is the name that was listed in step 2

If you look on your computer in the directory that Command Prompt is pointing to e.g. C:/Users/Ash then you’ll see a copy of that .apk file that you just backed up

Deleting Apps

Note: PLEASE make sure you’ve backed up any applications before deleting them.
Also, be sure that you’re not deleting any important system apps like Rosie (the HTC Sense framework!). Deleting things like Quick Office, Peep, Teeter, Facebook etc is fine.

Enter shell mode again by typing: adb shell

Type: cd system/app
This takes you into the system/app folder

Type: ls
This will show you a listing of the apps (.apk files) in the folder

Type: rm <full_name_of_app.apk>
where <full_name_of_app.apk> is the name that was listed in step 2
This deletes the application permanently from your phone

If in step #3 there was a <full_name_of_app>.odex file as well as .apk then delete that too using: rm <full_name_of_app.odex>

Rebooting

Once you’re done deleting your applications you can restart your phone and if everything went well then it will start normally and you’ll find that the deleted applications no longer show up in your app drawer.

Restoring Applications

If for whatever reason you decide that you want to reinstall those system applications you backed up, you can do the following:

Make your system partition writable using the steps in Making the System Partition Writable